Electron discharge device having a cavity resonator provided with a tuning electrode



April 18, 1950 M0 DULATIUN VOLTAGE ELECTRON DI W. E. $HOUP ARGE DEVICE HAVING A CAVITY RESONATOR PR IDED WITH A TU I G ELECTRODE Filed Sept.

INVENTOR ATTORNEY Patented Apr. 18, 1950 a; 1', --s reemie 2 i UNITED STATE-S PATENT QFF ICE 23504339 'ELECTBONPISQHARGE hhvI'oE *A puppy acsom 'ron PROVIDED WITH A TUNING ELECTRODE William ShouppflWilkins burg, Ba", ass ignor t Westinghouse Electric Corporation, Ea's't 'Pittsburgh, Ta, a corporation 'of Pennsylvania ififlplfzitioh sepfoinber 27, 1'944,Seflal No. 5555943 mfola'ims. (o1. s1=5- 4b") i rhts mventien relates to 'electron discharge deames generally referred "to as magnetrons, and vmrtmumnyw "tuning 'mean's for the same.

51' 're'eezit mevelopmen t in this art has been termehwsrown a: thorns :as somewhat 'fles'criptii e oftmii'rrg means f'or a magnetron, and -coiisistltg 6f a plurality of wrongs, one in each flit fsei eral resonant *oavities or a magii'etron, and

carried from a complete or partial ring 'at the anus 6f tlie ctivities the s'eye'ral :pro'ngs "may he mo'ved iongitudinally and simultaneously in tnea azvinesitheringes:mechamcany connected my r ed m1- lver through a ii'exible part,=such as a 'aieildws or diaphragm so as to-obtain mechanical eoritrol of movement and posit'ion of the "crown air tnnnrs"within tne magnetron. hside from'the mecl-fanical dimculties dfis'ealing, lateral displaoement ann theinkertnat strneturealso has'tne idisadvantage; ror enablin the :ring to be :meved, '-of acquiring a ra'rger' ena space Im the ma'gnetron 'withirestiltant greater spacing a art 0f the :pole igiiecesof tlfe h-fagnt than in theiueual magntron where no cr own of thorns is -"'e-"mployed.

BroadIy stated, *then, an object 'of the ipr'esent mvefltioh is t'o proyide a tuning means and/or a ereouemsy modulation means for a magnetron *whmn wflmccompiisn tuning by electrical in'eththereby avoiiiin'g th'e Iadverse structured and operational characteristics rel'ated afbove -'for the crown of thorns method.

liih'ewfise of general-nature, the invention contemplates-operator control of internal tuning means biit without transitional movement "of hie'chninism .lirom 'exterior "to interior of the ima ematron.

More an :detail, the invention. has for an object to provide a l capaoita'tive tuning means within a =mhbttdnwh-ile maintaining the epri'or art dimensional charaeteristic's' of the magnetron.

-=Another obliect of the invention is to felectrican? control th'e fimctioning 0f the tuning means inomith'efexteriormrthemagnetron.

.Yet another-object the iiivention rissto apply *itative tuniug most v"eil'ectivelysin the run.

#Other mbjects-ro f the invention will appear to those skilleu :in the cart as the description :proigresses, ib'oth y directaecitation thereof and by inference rrom the'context.

to the accompanying nr'awm'g's in nfifii'ei' al's as reference i dicatie simiiarqoartstnrtughout the severaWrews rigors .1 as an genial-1y seiqgrtuuinai section of ii. ifiaghetrtin snowingrriy improved-tuning therein"; I

is a plan oFtheoons't-i'uction of Fig. 1, but with the cover -iir=hfl plate removed; and

Figure is a detail sectional viewer a part of the magnetron ason t me (if 2., sh'oiilmazes.-

In its-general aspects, the invention provides fixed means within the endspaces of the magnetron, -here #shown as rings, between which extend a plurality of tuning elements. Each Ituning elementpasseslongitudinally through a, const1 icted :part of one of the resonantcavitiesof the magnetron, and is .shown eccentric to vthe cylindrical part of suchcavityhere depicted as ;using that conventional shape. The invention. "however, is not limited to this shape of cavity and -location of tuning element. Furthermore, while the present showing s'hows one of the jtuning elements in each resonant'cavity, -it--is within the scope of the invention to utilize the tuning elements in any number of the resonant cavities desired-and for range of tuning which thenumber employed will-accomplish. I

Referring now specifically to the embodiment of the invention illustrated in the several-figures, the reference numeral =l0 designates .a cylindrical metallic magnetron body, the ends whereof have cover or end plates i l sealed therein that the interior may be evacuated. Within and as an integral :part 01 said body the usual magnetron anode structure 12 of generally cylindrical-shape but shorter-than the outer part oi-the body-so as -to"-provide end spaces l3 between the anodea-nd said end plates I. Tl-1e anodeastructure is axially hollow to provide a cathodecavity and radiating from this cathode cavity are a vplurality 'of resonant cavities 14, each havingin the form shown a cylindrical ,portion ,parallel to the cathode cavity and each cylindrical portion havinga longitudinal constricted capacitativeslot I 5 constituting-a lateral opening from the cylin drical ;portion of the cavity :into the hollowcentral :part of cathode chamber of the magnetron. Said-slots 15 extend the fulllength-of the anode body so as to be open at their ends into said end spaces 43. -The ends-of the cathodecavity and the ends =01 said resonant cavities likewise open-into the end-Spaces--l-3. A

ta cathode tfipa'sses axially through the cathode cavity, adequately spacedtrom theanoderand supportedas usual --from :lead-in rods 11 enterthe same relation to 'the mag netroniandi its afiioszl'e as 'e'i, ts-inmagrretrons asj heretoforemsed. 1111 5a ih'g 00:13 the fire S elli; invention, 58. ring I9 Shoii'l'h concentr cally situatea i h aioh'bhd 7 walliii' the coeeascsee sen lias f tially locating'th'e ring is proximity to the collar-like part of the magnetron body portion so as not to be opposite the several resonant cavities any more than necessary and thus removed from interception of the magnetic lines of force from the ends of the cavities.

A lead-in rod 20 entering at one side of the end space, free of contact with the end space wall, is welded or otherwise secured to the ring, and affords physical support thereat for the ring and electrical connection to the exterior of the magnetron. Said lead-in rod is introduced through a hollow housing 2| sealed to the magnetron body and internally sealed with appropriate insulationas usual with lead-in rods of this char-- acter. At parts of the rings at intervals from 'saidlead-in rods, are provided insulated struts '22 from the anode body for holding said ring rigidly in place. 7

A tuning electrode 23, shown in the form of a filament, extends longitudinally of at least one fslot l5, and in the present showing such an electrode is provided in each said slot. Each said tuning electrode has ends thereof protrudinginto the end spaces l3, and those ends are secured, as

by spot welding, to radially disposed spring tensioning arms 24, one at each end of each elec- 'trode, andthe outer ends of said arms are secured, as by spot welding, to the respective rings -I9. The invention contemplates optional choice 'of tuning electrode construction, material and operation. For instance, said tuning electrode may be a hot cathode, emissive of electrons due to heat generated by an electric current travers- ,''ing the said cathode by virtue of connection through the arms, rings and lead-in rods. Control of the current thus applied to said tuning electrodes will vary, as desired, the electron emission from said tuning electrodes.

} 7 If so desired, in addition to-a heating current for said tuning electrodes, a modulation voltage may be applied from the exterior to one ring and to the anode, in which event variation in the modulation voltage efiectlve between the tuning electrode and the anode may be utilized as the tuning means with or without altering the current applied for heating the tuning electrode. Again, if preferred, said tuning electrode may be of a character which readily emits secondary electrons released by bombardment. Such bombardment may be obtained in part by electronsfrom the cathode l6 of the magnetron and in part by electrons returning to said tuning electrode. To render the tuning electrode effective for tuning purposes whenthus excited with secondary emission, a modulation voltage is applied, as above described,

between said tuning electrode and the anode, but

' the source of heating current for the tuning electrode would be omitted.

' 'In' operation, electrons will emerge from the The electrons will describe an orbit due the electrons from the tuning electrode and 'within the constricted capacitative part of the :.magnetron cavity will alter the dielectric constant of the space and consequently the resonant frequency of the cavity will be altered. This alteration inresonant frequency will cause a tuning or frequency shift of the magnetron.

, Specifically with reference to the tuning elecing of the emission will occur due to the collision with the tuning electrode of a few of the electrons from the magnetron cathode. Secondary electrons thereby become emitted and in normal cycle return. to the electrode, thereby causing other electrons to emit, thereby releasing more electrons, thereby building up the emission from the secondary electrode rapidly. Conditions are therefore peculiarly suitable for the use of a secondary emission electrode, since no heater current is required and the operation requires none of the electrons from the tuning electrode to strike or lodge upon the anode body. A modulation voltage supply to deliver direct current will therefore not be required, but will only be needed to supply alternating current necessitated" by; the oscillators shunt impedance. As the modulation voltage is varied, the electrons from the tuning electrode will vary their average distance from that electrode and consequently will modify-the for the purpose, such as alloys of silver-magnesium, beryllium-copper, pure-beryllium or other substances or alloys used either as the entire body of the electrode or as a part or coating therefor. Furthermore, while the tuning electrode is shown and preferably is situated in the constricted or slot portion of the cavity; its essential location is more broadly defined as eccentric to the axis of the cavity and somewhat more specifically as in proximity to the constricted portion of the cavity.

I claim:

1. An electron discharge device having a cathode and anode with cavity resonators in the anode having constricted portions, tuning means longitudinally disposed in a cavity resonator in proximity to a constricted portion and projecting out of opposite ends of said cavity resonator, and means mounting said tuning means by said-pro jecting ends with the 'major portion of said tuning means in said cavity resonator.

2. An electron discharge device havinga cathode and an anode around the cathode, said anode having a cathode cavity and having cavity resonators opening intosaid cathode cavity, and electron emissive tuning means longitudinally disposed in one of said cavity resonators in proximity to the opening of a cavity resonator into the cathode cavity, said tuning-means having a cross-section negligible in size compared to said cavity resonator whereby the cavity resonator is unobstructed to electrical lines of force longitudinal of said cavity resonator and tuning means.

3. An electrondischarge device having a cathode and an anode around the cathode, said anode having a, cathodecavity and having a substantially cylindrical cavityresonator opening lateryally into said'cathode cavity with a constricted strode functioning as a secondary emitter. star 76 openin and a tuning electrode parallel to said cathode and eccentrically disposed with respect to said cylindrical cavity resonaton- A V 4. An electr q le teedevi ehavinsa gathode and an anode around the cathode, said anode having a cathode cavity and having a cavity resonator the major part whereof is substantially cylindrical, said cavity resonator opening laterally into said cathode cavity with a constricted opening, and a tuning electrode in said constricted opening.

5. An electron discharge devic having a cathode and an anode with a cathode cavity and cavity resonators in the anode and with con- E having substantially cylindrical portions axially parallel to the cathode, and tuning means in one of said resonators axially eccentric thereto and substantially coextensive with the axial length of said resonator.

7. A magnetron comprising an enclosure, an anode body within the enclosure spaced from the ends thereof providing end spaces within the enclosure, said anode body having a cathode cavity and cavity resonators extending from one to the other of and opening into both said end spaces, a cathode in said cathode cavity, supporting rings in said end spaces concentric with the cathode and of greater diameter than the cathode cavity, and tuning electrodes supported from said rings and extending the length of and each within a cavity resonator.

8. A magnetron comprising an enclosure, an anode body within the enclosure spaced from the ends thereof providing end spaces within the enclosure, said anode body having a cathode cavity and cavity resonators extending from one to the other of and opening into both said end spaces, a cathode in said cathode cavity, supporting rings in said and spaces concentric with the cathode and of greater diameter than the cathode cavity, insulating mounting means for said rings interposed between said rings and the anode body, and tuning electrodes supported from said rings and extending the length of and each within a cavity resonator.

9. A magnetron comprising an enclosure, an

anode body within the enclosure spaced from the ends thereof providing end spaces within the enclosure, said anode body having a cathode cavity and cavity resonators extending from one to the other of and opening into both said end spaces and extending laterally from the cathode cavity and providing a constriction next to and opening into said cathode cavity, supporting rings in said end spaces concentric with the cathode and of greater diameter than the cathode cavity, and tuning electrodes supported from said rings and extending the length of a cavity resonator and each within a constriction of a cavity resonator.

10. A magnetron comprising an enclosure, an anode body within the enclosure spaced from the ends thereof providing end spaces within the enclosure, said anode body having a cathode cavity and cavity resonators extending from one to the otherof and opening into both said end spaces, a cathode in said cathode cavity, supporting rings in said end spaces substantially overlying a part of each cavity resonator, radially directed tensioning arms secured to said rings, and tuning electrodes supported from said tensioning arms and extending the length of and each within a cavity resonator.

11. A magnetron comprising an enclosure, an anode body within the enclosure spaced from the ends thereof providing end spaces within the enclosure, said anode body having a cathode cavity and cavity resonators extending from one to the other of and opening into both said end spaces, a cathode in said cathode cavity, supporting rings in each of said end spaces and substantially next to the peripheries of said end spaces, tensioning arms secured to said rings and projecting radially inward thereof, and tuning electrodes supported between pairs of said arms in said resonators.

12. A magnetron comprising an enclosure, an anode body within the enclosure spaced from the ends thereof providing end spaces within the enclosure, said anode body having a cathode cavity and cavity resonators extending from one to the other of and opening into both said end spaces and extending laterally from the cathode cavity and providing a constriction next to and opening into said cathode cavity, supporting rings in each of said end spaces at a part thereof remote from the said constriction of the cavity resonator, a tensioning arm secured on said ring and projecting therefrom to a position overlying said constriction,'and a tuning electrode supported from said tensioning arm and located in said constriction.

13. A tunable magnetron comprising a single anode having cavity resonators, and two cathodes insulated from each other and from said anode, said anode functioning as such for both said cathodes, each said cathode having means coupled thereto for applying a difference of potential between it and said anode and for applying to the two cathodes potentials differing from each other, whereby emission from one cathode is adapted to produce high frequency oscillations in the magnetron and emission from the other cathode is adapted to tune said oscillations over a band of frequencies inclusive of the produced high frequency oscillations.

14. A tunable magnetron comprising a single anode having cavity resonators, and two cathodes insulated from each other and from said anode, said anode functioning as such for both said cathodes, each of said cathode having means coupled thereto for applying a difference of potential between it and said anode and for applying to the two cathodes potentials differing from each other, whereby emission from one cathode is adapted to produc high frequency oscillations in the magnetron, and a source of modulation voltage connected to the said potential applying meansof the other cathode for varying the said oscillations over a band of frequencies inclusive of the produced high frequency oscillations.

WILLIAM E. SHOUPP.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,063,342 Samuel Dec. 8, 1936 2,241,976 Blewett et al May 13, 1941 2,270,777 Von Baeyer Jan. 20, 1942 2,338,237 Fremlin Jan. 4, 1944 2,408,234 Spencer Sept. 24, 1946 2,412,372 Usselrnan Dec. 10, 1946 

